1. Technical Field
The present invention relates to an electricity distribution device connected to a system power supply, and capable of supplying power to a load from a power source other than the system power supply when performing self-sustained operations.
2. Description of the Related Art
In recent years, consumers are provided with system power supplies separate from distributed generation supplies such as battery devices, solar power generators, and so forth, and there are known system interconnection devices which perform system interconnection to supply power to the consumer from both the distributed generation supply and the other system power supply, or perform self-sufficient operation where the consumer is supplied with the distributed generation supply alone (e.g., see International Publication No. 2013/015192).
However, there has been demand in the conventional art for estimating the life expectancy of a battery back of the electricity distribution device without increasing the number of parts of the electricity distribution device.